Synopsis Other Factual Information Elite 5512 and Elite 5516 were both in the same Gander ACC sector, monitoring the same frequency. A review of the Gander ACC communications tape indicated that the Gander controller instructed Elite 5512 to contact Moncton ACC on frequency 132.8 MHz. The first officer of Elite 5516 responded quickly, said 28 thanks and switched to Moncton on 132.8 MHz. An aircraft's identification or call-sign must be included in any radio transmission. The crew of Elite 5512 had not heard nor acknowledged the instruction for them to contact Moncton on 132.8 MHz. Elite 5516 contacted the Moncton ACC controller on 132.8 MHz, and the first officer requested and received clearance to climb to FL390. During the hand-off from Gander ACC and the climb to FL390, the captain of Elite 5516 was not on the flight deck. The Canada 3000, Boeing 757, Standard Operating Procedures (SOP) manual requires that the other flight crew member confirm important directions, such as altitude changes, before they are complied with. During the occurrence, the Moncton ACC Heath Point Sector was staffed with a controller trainee who was being supervised by an on-the-job instructor (OJI). The traffic volume during the occurrence was assessed as light with normal complexity. All equipment available and used by the controllers was functioning properly. The radar display was configured to display data tags only for the aircraft targets transiting through the Heath Point Sector, such as Elite 5512; the track for Elite 5516 and AAL 53 was outside the Heath Point sector. The controller trainee had a target displayed as Elite 5512 on his radar when Elite 5516 established radio contact. The controller trainee asked Elite 5516 to confirm 5516 and not 5512. The pilot replied that their aircraft was Elite 5516, but there was another Elite, 5512, airborne as well. The controller trainee believed that the Elite 5512 target displayed on his radar was in fact Elite 5516 and the aircraft to which he was talking. He did not use any additional means to confirm aircraft identification. The controllers reported that sometimes the aircraft identification data displayed on the radar is erroneous. The controller trainee checked that there was no traffic confliction for the radar target displaying the Elite 5512 data tag and cleared Elite 5516 to climb up to FL 390. During the period that the controller trainee accepted the hand-off and cleared Elite 5516 to climb, his OJI was momentarily distracted by a group of former Transport Canada employees that was being given a tour of the Moncton ACC. When the OJI returned his attention to what the controller trainee was doing, he noticed that the Elite 5512 target had not started to climb. The radar's all function was selected to display all aircraft targets, and the OJI saw the Elite 5516 target over Natashquan climbing. The OJI immediately instructed the controller trainee to clear Elite 5516 back down to FL 370, which he did. In 1990, the Canadian Aviation Safety Board (CASB), as a result of a special investigation into air traffic control services, stated that inattention or lack of vigilance appears to be contributory in approximately 50 per cent of all ATS occurrences, and that these types of errors often happen during periods of light, non-complex traffic.